import pygame
from pygame.sprite import Sprite

class Ship(Sprite):
    
    def __init__(self,ai_settings,screen):
        #初始化飞船并设置其初始位置
        super(Ship,self).__init__()

        self.screen = screen
        self.ai_settings = ai_settings

        #加载飞船图像并获取其外接矩形
        ship_image = pygame.image.load('images/ship_1.bmp')
        ship_weight, ship_height = ship_image.get_size()

        # 缩放图片
        self.image = pygame.transform.smoothscale(ship_image, (ship_weight//5, ship_height//5) ) 
       

        #self.image = pygame.image.load('images/ship_1.bmp')

        self.rect = self.image.get_rect()
        self.screen_rect = screen.get_rect()

        #将每艘飞船放在屏幕底部中央
        self.rect.centerx = self.screen_rect.centerx
        self.rect.bottom = self.screen_rect.bottom

        # 在飞船的属性center中存储最新值
        self.center = float(self.rect.centerx)

        # 移动标志
        self.moving_right = False
        self.moving_left = False

    def update(self):
        #根据移动标志调整飞船的位置
        #更新飞船的center值，而不是rect

        if self.moving_right and self.rect.right < self.screen_rect.right:
            self.center += self.ai_settings.ship_speed_factor
        if self.moving_left and self.rect.left > 0:
            self.center -= self.ai_settings.ship_speed_factor

        # 根据self.center更新rect对象
        self.rect.centerx = self.center


    def blitme(self):
        #在指定位置绘制飞船

        self.screen.blit(self.image,self.rect)

    def center_ship(self):
        #让飞船在屏幕中央
        self.center = self.screen_rect.centerx